Non-Uremic Calciphylaxis: An Unexpected Complication With Recombinant Human Parathyroid Hormone

Calciphylaxis is a rare syndrome of calcific microvascular occlusion, whereas non-uremic calciphylaxis (NUC) is a subset of this disease in which renal impairment is not observed. Recombinant human parathyroid hormone (rhPTH) (1-84) is a medication approved for the management of hypocalcemia in patients with hypoparathyroidism. We present a case report of a 38-year-old woman with postoperative hypoparathyroidism treated with rhPTH who subsequently developed calciphylactic lesions on her abdomen. Multidisciplinary interventions included intravenous and intralesional sodium thiosulfate therapy, laboratory monitoring, dermatological wound care, and pain management. Calciphylaxis can rarely be precipitated by rhPTH due to its effect on calcium and phosphorus balance even in the setting of normal renal function. The use of calcium and calcitriol supplementation, complicated by factors such as female sex and obesity, may have contributed in this patient's case. Hence, regular follow-up with tapering off of calcium and calcitriol supplementation is important in patients receiving rhPTH.